Lead exposure threatens the health of millions of children, yet it is entirely preventable health problem. Our project objective is to develop an advanced blood lead test to identify and protect those at risk through blood lead screening tests of children. Even very low lead exposure, measured by blood lead levels, causes irreversible damage, especially in very young children, resulting in decreased IQ, learning disabilities, attention deficit disorders, behavioral problems, stunted growth and other serious individual and societal problems. The US Department of Health and Human Services has established an ambitious goal of eliminating lead poisoning in children. The Centers for Disease Control has lowered the level of blood lead that calls for concern down to 5 g/dL, with predictions of settin a lower level of concern in the near future. It is generally agreed that no level of lead exposure s safe. To aid in this public health effort, we propose to develop a new, needed, clinical blood lead test. The Aims of our Phase II research and development project are to produce and validate a low- cost diagnostic product by (Aim 1) developing an innovative 8 sensor platform capable of sensor-based measurement of blood lead levels, by (Aim 2) developing the platform to meet current and emerging needs of accuracy and precision over the entire range of measurement for child tests down to blood lead levels of 1 g/ dL using a single drop of blood, by (Aim 3) producing a new proprietary Metexchange(r) reagent, containing no toxic chemicals that effectively lyse RBC and releases Pb2+ for sensitive and accurate ASV analysis of blood lead levels over the entire clinical range, without bias to Graphite Furnace Atomic Absorption Spectroscopy (GFAAS), and by (Aim 4) validating accurate, precise and sensitive measurements of total lead levels in clinical blood specimens over the entire range, equal to or better than GFAAS. No system yet accomplishes this.